The present invention relates to beach erosion protection and restoration structures and, more particularly, to slotted prism-shaped modules adapted to be placed in side-by-side relation to define an offshore reef-like barrier.
Many forms of breakwater structures have been proposed to retard beach erosion by resisting or calming wave energy. Prior arrangements include permeable or perforated seawalls located along beach surfaces or exposed shorelines for breaking the force of incoming waves and causing the deposit of suspended sand. Examples of prior patents disclosing such structures are U.S. Pat. Nos. 2,191,924 and 2,474,786, each issued to H. J. Humphrey; U.S. Pat. No. 2,755,631, issued to D. H. Hayden; U.S. Pat. No. 3,387,458 issued to G. E. Jarlin; U.S. Pat. No. 3,844,125 issued to J. D. Williams; and U.S. Pat. No. 3,894,397 issued to S. S. Fair. While each of these patented structures offer some measure of control to reduce or minimize beach erosion, they have not provided a solution to the problem of stopping and reversing the erosion process.
Among the faults of the prior structures is that they are not only expensive to install but are objectionable because of their adverse affect on the aesthetic and recreational use of the beaches. Further, the wave energy-resistant character of seawall-like structures shorten their service life and cause beach erosion along their frontal areas.
The present invention proposes to solve these various problems and limitations of prior erosion control devices by providing an offshore reef-like system comprised of prism-shaped slotted modules which are placed in side-by-side array in a surf or wave breaking area. The modules not only stop shoreline erosion from high water and wave action, but contribute to beach restoration when sedimentation is available.
It is an object of the present invention to provide an off-shore beach erosion-preventing precast concrete module including one or more flow control passages for dissipating energy of incoming waves and retaining outgoing waves to provide sedimentation while attaining a minimal air-liftable load to enable installation by helicopter.
It is another object of the present invention to provide a beach erosion-preventing module as set forth above which is adapted to seat itself in a fixed manner on off-shore wave breaking surf floor areas ranging from silt or sand conditions to rocky or coral conditions.
It is yet another object of the present invention to provide a beach erosion-preventing module as set forth above which minimizes impacting wave forces tending to overturn the module.